FARMINGTON, N.M.  Environmentalists are fighting a proposal to build another coal-fired power plant in the Four Corners area, saying the region cannot handle more pollution.

Environmental groups have detailed 27 problems with the draft air permit for the proposed Desert Rock Power Plant that would be built south of here.

The U.S. Environmental Protection Agency released the air permit in July. It sets limits for six pollutants.

The 10 environmental groups argue the permit should limit mercury and carbon dioxide, which the EPA said will be addressed in an environmental impact statement expected to be released in December.

Mike Eisenfeld, a member of the San Juan Citizen's Alliance, said if separate documents address the pollutants, those should have been given to the public.

Houston-based Sithe Global Power and the Navajo Nation's Dine Power Authority plan to build the $2.5 million, 1,500-megawatt power plant that would produce enough electricity for up to 1.5 million homes in the Southwest.

The project would bring in about $50 million a year in taxes and royalty payments for the tribe, making it the largest economic development project to be undertaken by the Navajos.

Frank Maisano, a spokesman for Sithe, said his company has put more than two years of work into developing the air permit, and it should not be scrapped.

"Just picking up the ball and leaving doesn't accomplish the goals of meeting the reliability needs of the region," he said. "It doesn't meet the economic needs of the Navajo Nation and the Four Corners and, frankly, it would have a negative impact on the environment and the region."

Eisenfeld said Sithe portrays itself as a victim of the area's two existing coal-fired power plants.